Antarctic vascular plants in non-Antarctic habitats: Leaf trait covariation across Central Chilean, Patagonian, and Antarctic populations

Colobanthus quitensis and Deschampsia antarctica are the only vascular plants naturally inhabiting Antarctica, yet they are also found in non-Antarctic habitats such as Patagonia and the southern Andes. This raises the question of whether the environmental conditions across these regions are associated with contrasting leaf functional traits among geographically distinct populations of these iconic species. We combined structural and functional leaf traits from in situ and common environment experiments to assess how populations from Antarctica, the Andes and Patagonia, differ in leaf structural, photosynthetic, and hydraulic traits and whether these differences persist under common growth conditions. Plants from Antarctica exhibited distinctive suite of traits, including higher leaf mass per area and density, lower mesophyll conductance and hydraulic conductivity, and particularly in C quitensis , higher maximum bulk modulus of elasticity. Importantly, patterns of trait covariation differed among populations and growth environments, indicating that relationships among structural, gas-exchange, and hydraulic traits are context dependent. Overall, our results reveal substantial geographic variation in leaf functional traits and show that some population differences persist whereas others diminish under common growth conditions, suggesting contributions from both population differentiation and environmental responses.